ISS Risk Mitigation

Enhanced Dynamic Load Sensors (EDLS) on Mir

EDLS Sensors Experiment Support Module

Objectives

The Enhanced Dynamic Load Sensor (EDLS) experiment is designed to measure the crew-induced forces and torques imparted on the Mir habitat module's interior surfaces. The EDLS hardware measure the magnitude and frequency of the crew-induced disturbances of the Mir microgravity environment.

Shuttle-Mir Missions
Mir-21 - Mir-23, NASA-2, NASA-4

Approach
EDLS hardware (experiment support module and torque/force sensors) was transported to Mir and installed in the Mir Priroda module in 1996. The sensors consisted of a handhold, a touchpad, and two foot restraints. The EDLS experiment involved two types of operations: passive and active. Passive session refers to the use of the sensors during nominal on-orbit activities (such as push-offs, landings, and support). Active sessions refers to the use of the sensors to record forces associated with throwing a small ball at a target.

Approximately 20 EDLS sessions (18 passive and 2 active) were performed during the Mir-21/NASA-2 missions between May and August of 1996. Failure of the experiment support module (ESM) during NASA-2 prevented experiment operations during the Mir-22/NASA-3 missions. The original ESM replaced with similar ESM for MiDSE experiment in 1997, allowing experiment operations to resume during the Mir-23/NASA-4 missions. Approximately 15 high quality EDLS sessions, 10 passive and 5 active, were performed during Mir-22/Mir-23/NASA-4 missions from February through May of 1997.

Results
Analysis of data collected indicated that the crew loads induced on module internal structures were no greater than 70 Newtons at a frequency of range from 0 to 10 Hertz (Hz). An order of magnitude reduction in loads (from crew motions such as push-off, orientation, and landing) as compared to initial data collections was shown. The reduction is due to the zero-G experience gained by the crewmembers who, as their time in the zero-G environment accumulates, learn to minimize the their efforts to perform the intended motions thus reducing the loads imparted to the spacecraft structure and EDLS.

The Phase 2/3 benefits from this experiment is that restrictions in crew motions that were originally envisioned can be reduced for crewmembers possessing sufficient time on orbit to achieve the above-mentioned learning experience.

Publications
Lofton R, Conley C. International Space Station Phase 1 Risk Mitigation and Technology Demonstration Experiments. 48Th International Astronautical Congress; 1997 Oct 6-10; Turin, Italy; International Astronautical Federation.

Newman DJ, Tryfonidis M., van Schoor M. "Astronaut-Induced Disturbances in Microgravity," AIAA J. Spacecraft and Rockets, March-April, 1997.

Newman DJ, van Schoor M. "Dynamic Load Sensor Experiment: Background, Science Requirements, and Preliminary Design," white paper, November 18, 1992.

Newman, DJ, "Dynamic Load Sensors (DLS) Spaceflight Experiment," report and world wide website, http://web.mit.edu/aeroastro/www/labs/DLS/, MIT, Dept. of Aeronautics and Astronautics, MVL Report 96-1, January, 1996.

Dynacs Engineering Company. ISS Phase 1 Risk Mitigation Experiments and Technology Demonstration summaries and Lessons Learned. ISS Phase 1 RME Forum. JSC 28080 Revision A. Houston, TX. August 1998.

Principal Investigators
Sherwin Beck
NASA/Langley Research Center

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